Field of the Invention
This invention relates to a novel refillable column for chromatography at elevated pressure. More specifically, this invention comprises a device which can be repeatedly packed with a chromatographic material, emptied of such material when it is exhausted, or it is desired to employ a different material, and repacked with a fresh adsorbent by one of ordinary skill in the chromatographic art.
Prior Art
The process known as chromatography is old in the chemistry art. It is a means for separating chemical compounds, especially closely related ones, by allowing a solution of a mixture to seep through, or along, an adsorbent medium so that each compound becomes adsorbed in a separate layer, section, or portion of the adsorbent.
The chromatographic art has evolved steadily and, at times, dramatically from the early process known as open column chromatography to the highly sophisticated and useful chromatographic processes at elevated pressure commonly utilized today. Chromatography under pressure aids in the definitive separation of minute quantities of very closely related chemical compounds. In some instances pressure as great, or greater, than 100 atmospheres are employed in the process. For example, the analysis of blood to identify metabolites of physiologically active agents, which may be present in quantities measured in parts per billion, is often carried out at pressures of 1500 to 2000 psig, or higher.
A large number of highly refined adsorbents are available for use in high pressure chromatography. One, and not infrequently, a plurality of adsorbents is packed into a column providing a bed of adsorbent material having a length, or depth, several times greater than its cross-section (generally, diameter). The fluid mixture (solution) of the compounds desired to be separated is slowly percolated through the adsorbent bed. The pressure on the adsorbent bed can range from one to many atmospheres. The pressure can be varied by applying pressure, as with a pump, at the inlet to the column and restricting the rate of flow at the outlet from the column.
All sorts and varieties of columns for chromatography at elevated pressure, both packed with adsorbent and unpacked, are commercially available. Many of the pre-packed columns are not reuseable. Once the adsorbent has been exhausted (or poisoned) the column is no longer useful and must be replaced. Moreover, when a different adsorbent is desired, or needed, an entirely new column must be employed.
Some of the unpacked columns available commerically which can be packed by the user become single application columns once they are packed because they cannot be emptied and repacked because of their design.
Some of the refillable columns for chromatography at elevated pressure which are available are so designed that skilled hands are required to achieve an effective seal after the column has been repacked. Consequently the emptying and repacking of such columns is slow, cumbersome and expensive because of the level of skill required to satisfactorily accomplish the refilling operation.
Accordingly, it is an objective of this invention to provide a refillable column for chromatography at elevated pressure that can be readily emptied, repacked with the same or different adsorbent and resealed positively against pressure leaks with a minimum of time and skill.